The diabetic condition affects millions of people in the United States. Among the afflicted population, a significant percentage of persons develops problems associated with the lower extremities, namely, the foot and lower leg. In the diabetic, the foot represents an area which is repeatedly subjected to minor trauma which may be far more serious than in a healthy individual. Injury to the diabetic foot can result in ulceration which appears superficial, yet is capable of persistence and can lead ultimately to extensive tissue damage, gangrene of the feet or toes, systemic infection, and possibly may necessitate amputation of the compromised limb.
The long-term diabetic is unusually susceptible to a number of pathologic conditions, including macrovascular and microvascular disease. Arterial disease, including vascular occlusion of the lower extremities, is particularly common among the adult diabetic population.
In addition to arterial disorders, the diabetic is subject to peripheral neuropathy, which usually first manifests itself in the lower extremities. The neuropathic condition can exist either in association with, or independently of, vascular insufficiency. For example, a foot with seemingly good blood flow, as determined by inspection of foot color, foot temperature, or pedal pulse, may nonetheless exhibit neuropathy and loss or impairment of vasomotor nervous function. Although the underlying physiology and pathology of the condition is not well understood, it is possible that, in a neuropathic foot with apparently sufficient circulation, blood is nonetheless unable to sufficiently permeate the capillary beds and microvasculature to properly supply adjoining tissue.
The sensory impairment accompanying neuropathy in the diabetic makes the diabetic unusually prone to serious injury. Diabetic feet may be traumatized or subjected to infection in the same ways as normal feet; however, in the case of the neuropathic foot, the injury may not be properly sensed by the patient. For example, a diabetic with an ulcerous lesion or foot callus will not always tend to shift weight off of the damaged area of the foot, thereby greatly exacerbating the extent of tissue damage before the injury is detected.
Diabetic foot ulcers are further characterized by their persistent nature, which may arise primarily due to the arterial insufficiency and neuropathy of the local tissue and the entire limb. It is known that increasing circulation in the affected limb, and hence the area of the wound, will tend to promote healing. An apparatus for promoting blood circulation to a patient's extremity is described in U.S. Pat. No. 4,590,925, issued on May 27, 1986. The ischemic foot is benefitted by the resulting increase in peripheral circulation, which facilitates delivery of normal blood constituents, as well as systemically administered drugs or antibiotics, to the site of the ulcer or wound.
A different approach to restoring lost blood factors and cells to a foot ulcer is referred to as "clot therapy". In this procedure, which has met with some success, amounts of a patient's blood are applied directly to the ulcer bed to promote clotting and wound closure. Alternatively, a solution is prepared from platelets isolated from the patient's blood and the solution is applied directly to the ulcer bed. An antibiotic may be added to the solution or to the blood sample to control infection. The disadvantages associated with clot therapy are the requirement for a blood sample from the patient and the inconvenience attendant to applying the solution, which may involve immobilizing the patient and elevating the patient's limb, for the period that the blood or solution is applied and allowed to dry.
In U.S. Pat. No.4,581,226, issued on April 8, 1986, a method is described for treating sensitive tissue, including foot ulcers, with a solution of processed seawater. The minerals, salts and other nutrient components of the processed seawater are disclosed to enhance healing of an ulcerous foot wound when applied as a soak solution.